The present invention relates to a wood pulper of the kind in which wood is fed via a hopper having advancing elements arranged on two opposing sides by which the wood is advanced to a grinding stone.
A wood pulper of this kind is described, for example, in German Published Patent Specification No. 1,461,582. In this pulper, the wood is advanced to the grinding stone by advancing elements consisting of endless revolving contoured chains having projections thereon, which pick up a pile of wood and press it against the grinding stone. There is a difference in speed between the chain speed and the wood speed which increases with increasing compression towards to the surface of the grinding stone, however, and this results in an uneven compression of the wood and thus uneven loading of the contoured chain. Although virtually no force is expended by the contoured chain in the feed-in or starting zone of the hopper, the force expended rises approximately parabolically from approximately the center of the hopper onwards.